The processing of photosensitive material involves a series of steps such as developing, bleaching, fixing, washing, and drying. These steps lend themselves to mechanization by conveying a continuous web of film or cut sheets of film or photographic paper sequentially through a series of stations or tanks, each one containing a different processing liquid appropriate to the process step at that station.
There are various sizes of photographic film processing apparatus, i.e., large photofinishing apparatus and microlabs. A large photofinishing apparatus utilizes rack and tank configurations that contain approximately 100 liters of each processing solution. A small photofinishing apparatus or microlab utilizes rack and tank configurations that may contain less than 10 liters of processing solution.
The prior art suggests that if the volume of the various tanks contained within various sizes of photographic processing apparatus were reduced the same amount of film or photographic paper may be processed, while reducing the volume of photographic solution that was used and subsequently discarded. One of the problems in using smaller volume tanks is that the inner and outer sections of the tank typically are fixed and not separable. Another problem in using low volume tanks is that the material being processed typically has a tendency to jam. Hence, it was difficult and time-consuming to separate the rack from the tank for cleaning and maintenance purposes.
One prior art low volume photographic material processing apparatus utilized photographic tanks having an inner rack section and an outer tank section that are easily separated. The processing apparatus contained a smaller volume of the same photographic solution that was previously used in regular-sized processing tanks. In fact, in some instances, the volume of photographic solution utilized in regular-sized tanks was reduced by as much as 90%. This apparatus permitted the inner rack section of the tank to be easily separated from the outer tank, while providing a narrow channel for both the photosensitive material and the processing solution.